From a3282538425ce9576408a6544d731f5777015290 Mon Sep 17 00:00:00 2001
From: Ben Nordick <ben@rigeltechnical.com>
Date: Thu, 24 Jun 2021 21:31:19 -0400
Subject: [PATCH] Improve supported product filter tree

---
 PolicyPlus/FilterOptions.Designer.vb |  2 +-
 PolicyPlus/FilterOptions.vb          | 36 ++++++++++++++++++++++++----
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/PolicyPlus/FilterOptions.Designer.vb b/PolicyPlus/FilterOptions.Designer.vb
index ab8f3db..3358d82 100644
--- a/PolicyPlus/FilterOptions.Designer.vb
+++ b/PolicyPlus/FilterOptions.Designer.vb
@@ -31,7 +31,7 @@ Partial Class FilterOptions
         Me.OkButton = New System.Windows.Forms.Button()
         Me.ResetButton = New System.Windows.Forms.Button()
         Me.RequirementsBox = New System.Windows.Forms.GroupBox()
-        Me.AllowedProductsTreeview = New System.Windows.Forms.TreeView()
+        Me.AllowedProductsTreeview = New PolicyPlus.DoubleClickIgnoringTreeView()
         Me.MatchBlankSupportCheckbox = New System.Windows.Forms.CheckBox()
         Me.AlwaysMatchAnyCheckbox = New System.Windows.Forms.CheckBox()
         Me.SupportedCheckbox = New System.Windows.Forms.CheckBox()
diff --git a/PolicyPlus/FilterOptions.vb b/PolicyPlus/FilterOptions.vb
index 42f9480..289f095 100644
--- a/PolicyPlus/FilterOptions.vb
+++ b/PolicyPlus/FilterOptions.vb
@@ -58,6 +58,19 @@
             Next
             AlwaysMatchAnyCheckbox.Checked = Configuration.AlwaysMatchAny
             MatchBlankSupportCheckbox.Checked = Configuration.MatchBlankSupport
+            ' Expand to show all products with a different check state than their parent
+            Dim expandIfNecessary As Action(Of TreeNode)
+            expandIfNecessary = Sub(Node As TreeNode)
+                                    For Each subnode As TreeNode In Node.Nodes
+                                        expandIfNecessary(subnode)
+                                        If subnode.IsExpanded Or subnode.Checked <> Node.Checked Then
+                                            Node.Expand()
+                                        End If
+                                    Next
+                                End Sub
+            For Each node As TreeNode In AllowedProductsTreeview.Nodes
+                expandIfNecessary(node)
+            Next
         End If
     End Sub
     Private Sub SupportedCheckbox_CheckedChanged(sender As Object, e As EventArgs) Handles SupportedCheckbox.CheckedChanged
@@ -110,11 +123,15 @@
         AllowedProductsTreeview.BackColor = If(AllowedProductsTreeview.Enabled, SystemColors.Window, SystemColors.Control)
     End Sub
     Private Sub AllowedProductsTreeview_AfterCheck(sender As Object, e As TreeViewEventArgs) Handles AllowedProductsTreeview.AfterCheck
-        If e.Node.Checked Then
-            For Each subnode As TreeNode In e.Node.Nodes
-                subnode.Checked = True
-            Next
-        End If
+        ' Recursively set the check state on child products only in response to the user
+        If e.Action = TreeViewAction.Unknown Then Return
+        PropogateCheckStateDown(e.Node)
+    End Sub
+    Sub PropogateCheckStateDown(Node As TreeNode)
+        For Each subnode As TreeNode In Node.Nodes
+            subnode.Checked = Node.Checked
+            PropogateCheckStateDown(subnode)
+        Next
     End Sub
 End Class
 Public Enum FilterPolicyState
@@ -130,4 +147,13 @@ Public Class FilterConfiguration
     Public AllowedProducts As List(Of PolicyPlusProduct)
     Public AlwaysMatchAny As Boolean
     Public MatchBlankSupport As Boolean
+End Class
+' The TreeView control has a bug: the displayed check state gets out of sync with the Checked property when the checkbox is double-clicked
+' Fix adapted from https://stackoverflow.com/a/3174824
+Friend Class DoubleClickIgnoringTreeView
+    Inherits TreeView
+    Protected Overrides Sub WndProc(ByRef m As Message)
+        ' Ignore WM_LBUTTONDBLCLK
+        If m.Msg <> &H203 Then MyBase.WndProc(m)
+    End Sub
 End Class
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